Even with all the recommended settings, and a very fast computer that is doing nothing except sending the data, it is maybe 50/50 that a 2 hour simulation can be conducted without an underrun. The longest run I have been able to do without an underrun is about 2.5 hours.
The sample rate is 12.5 Msamp/sec at 16 bit I + 16 bit Q or 400 Mbit/sec. For our application, that is unacceptable. I need to be able to run for days without data loss. It is a mystery to me why a 10 Gbit connection cannot support 400 Mbit/sec UDP reliably. Any ideas about how we can completely eliminate underruns? At the moment, I am uncertain whether the problem is occurring on the host or on the radio. I suspect the radio, but I will do some testing of the host to see what UDP data rate it can support without loss. Thanks! At 10:53 PM 4/10/2023, Marcus D. Leech wrote: >On 10/04/2023 21:12, Jim Schatzman wrote: >>The following steps had no impact: >> >>a) Don't use a switch but do a point-to-point connection between the >>comptuer's NIC and the N310. >>b) Adjust network buffers and ring buffer per recommendations (actually, the >>network buffers setting was always being done). >> >>Increasing the MTU to 9000 had a significant impact. An occasionaly underrun >>is still experienced, but an hour or two of continuous transmission is >>possible. >> >>I am wondering if this is not an issue on the computer side but on the radio >>side. Is the N310 incapable of supporting 1x 10 Gbps streams with a MTU of >>1500? Perhaps. >> >>I will do some computer-to-computer testing to see if the problem can be >>reproduced there. >> >>Jim >Even non-SDR applications tend to use jumbo-frames for continuous traffic at >10Gbit. I'm sorry that I didn't clue in to that > in the first round. > > >> >> >> >> >>At 08:39 PM 4/7/2023, Marcus D. Leech wrote: >>>On 07/04/2023 22:13, Jim Schatzman wrote: >>>>We have been unable to estable 100% reliable connections to an N310 USRP >>>>radio through its 10 Gbit ethernet from Linux. What happens is that it >>>>works fine for a period of time - 30 to 60 minutes, typically. Then we see >>>>a couple of U's in the output. Unfortunately, that is fatal for our >>>>application. >>>> >>>>Using the unmodified tx_samples_from_file or one modified to use separate >>>>threads to read data from the file and to sent it over the socket to the >>>>radio, the symptoms are the same. >>>> >>>>All the evidence is that the application is sending data continuously >>>>without any delays. Also, the "network" has no devices on it except for the >>>>host computer, a high performance 10G switch, and the N310 radio. >>>> >>>>We are wondering if this could be a Linux "feature". We would like to try >>>>increasing the socket priority with SO_PRIORITY. However, we are not >>>>finding any hooks in the UHD software for this. >>>> >>>>Suggestions? >>>> >>>>Thanks! >>>>Jim >>>>_______________________________________________ >>>Have you increased the ring buffers on your card? >>> >>>https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks#Increasing_Ring_Buffers >>> >>>Also, adjust the network buffers: >>> >>>https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks#Adjust_Network_Buffers >>> >>>Have you tried a direct connection--without the switch?à à à Just to >>>eliminate it.à Before you say "oh, it's not the switch", >>>à many "high performance" 10G switches have a less-than-ideal switching >>>fabric. >>> >>>_______________________________________________ USRP-users mailing list -- >>>usrp-users@lists.ettus.com To unsubscribe send an email to >>>usrp-users-le...@lists.ettus.com </x-flowed> >>_______________________________________________ >>USRP-users mailing list -- usrp-users@lists.ettus.com >>To unsubscribe send an email to usrp-users-le...@lists.ettus.com >_______________________________________________ USRP-users mailing list -- >usrp-users@lists.ettus.com To unsubscribe send an email to >usrp-users-le...@lists.ettus.com </x-flowed> _______________________________________________ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
